Refine: get started and input examples

In some cases, we want to refine the the calculation of a property based on previous results by using different convergence criteria like EDIFF and EDIFFG or higher ENCUT. If the parameter of init_from_suffix and output_suffix are both provided in the input file, refine would start based on the results in init_from_suffix directory and output the results to output_suffix directory. Otherwise, the calculation results would be output to the default suffix 00. An example of the input file is given below:

{
	"structures":	"confs/mp-*",
	"interaction": {
		"type":		"vasp",
		"incar":	"vasp_input/INCAR",
                "potcar_prefix":"vasp_input",
		"potcars":	{"Al": "POTCAR.al", "Mg": "POTCAR.mg"}
	},
	"properties": [
		{
                        "type":         "eos",
                        "init_from_suffix":	"00",
                        "output_suffix":        "01",
			"vol_start":	10,
			"vol_end":	30,
			"vol_step":	0.5,
                        "ediff": 1e-6,
                        "ediffg": -1e-3
		}
        ]
}

In this EOS example, refine would output the results to eos_01 based on the previous results in eos_00. The parameter for example ediff, ediffg, kspacing, and encut can be added in the properties part to quickly start the refine calculation. It should be noted that the current parameter for example vol_start, vol_end, and vol_step must stay the same with previous calculations to avoid the inconsistency of the task number.